Electrophotography can be used to create photographic quality multicolor toner images when the toner particles are small, that is, less than about 10 micrometers, and the receivers, typically papers, are smooth. Electrophotography typically involves the steps of charging a photoconductive element, exposing the photoconductive or dielectric element to create an electrostatic image, toning the electrostatic image, transferring the toner to a receiver, and fixing the toner to the receiver. A typical method of making a multicolor toner image involves trichromatic color synthesis by subtractive color formation. In such synthesis successive imagewise electrostatic images are formed on an element, each representing a different color, and each image is developed with a toner of a different color. Typically, the colors will correspond to each of the three primary colors (cyan, magenta and yellow) and black, if desired. The imagewise electrostatic images for each of the colors can be made successively on a photoconductive element by using filters for each color separation to reflect only the light corresponding to each color in the image to the photoconductive element. After developing each color separation, it can be transferred from the photoconductive element successively in registration with the other color toner images to an intermediate transfer member and then all the color toner images can be transferred in one step from the intermediate transfer member to a receiver. After all the color toners have been transferred to the receiver, the toners are fixed or fused to the receiver. To match the photographic quality produced using silver halide technology, it is preferred that these multicolor toner images have high gloss.
Commonly-assigned U.S. Pat. No. 5,258,256 discloses that toners having specified viscoelastic flow characteristics, as evidenced by a loss tangent of at least 1.2, used in a belt fusing system can provide desirable gloss. The belt in the belt fusing system, can be made of stainless steel or polyester. When polyester is used the belt can be formed solely of that material or it can be coated with a toner release layer. The outer surface of the fuser member can be aluminum, steel, various alloys, or polymeric materials, such as, thermoset resins and fluoroelastomers. Further, release agents may be used on the fuser belt. Commonly-assigned U.S. Pat. No. 5,708,948 shows an effective toner release layer coated on a substrate. This toner release layer has been found to be quite effective but there remain problems of its adhesion to the substrate.
The background art discloses several broad classes of materials useful for fuser belts. For example, commonly assigned U.S. Pat. Nos. 5,089,363; 5,362,833; 5,529,847; 5,330,840; 5,233,008; 5,200,284, and U.S. Pat. Nos. 5,465,146; 5,386,281; and 5,124,755 disclose fuser belts coated with toner release layers formed of silicone polymers. Commonly-assigned U.S. Pat. Nos. 5,089,363 and 5,708,948 disclose that fuser belts coated with a toner release layer formed of highly crosslinked polysiloxanes provide fused toner images having high gloss. Commonly-assigned U.S. Pat. No. 5,778,295, describes fuser belts containing a crosslinked, silicone resin intermediate layer and a toner release layer that comprises a silsesquioxane polymer.
While fuser belts described in the aforementioned prior art provide high gloss and good release of the fused toner images there is a need to improve the adhesion of the toner release layer to the substrate to promote belt life.